back|fire

back|fire «BAK _FYR», noun, verb, -fired, -fir|ing.

–n.

1. an explosion of gas occurring at the wrong time or in the wrong place in an internal-combustion engine: a) an explosion in the intake or exhaust, resulting from unburned fuel in the exhaust, or slow-burning fuel in the cylinder causing the new charge to ignite through the open intake valve. b) an explosion of gas occurring too soon in a cylinder.

2. an explosion coming out of the breech of a firearm.

3. U.S. a fire set to check a forest fire or other open fire by controlled burning off of the area in front of the forest fire.

–v.i.

1. (of gas) to explode at the wrong time or in the wrong place.

2. to have a result opposite to the expected result: »

His scheme backfired, and instead of getting rich he lost all his money.

3. U.S. to use a backfire in fire fighting.